LAUSR

Abstract Los Bifaces site, located in the Upper Tar River Basin, comprises an assemblage of at least 11 bifaces that were recovered on a surface of 2 m2. They show intermediate stages of manufacture and would have been deposited at the same time and in a grouped manner. The use of raw materials available in the region –despite the fact that the bifaces were not made at the site- and the high percentage of intentional fractures should be noted. Technological characteristics and their relationship with regional bifacial technology are described, and different hypotheses related to the artifactual assemblage formation are discussed, taking into account both natural and cultural aspects. Los Bifaces site is understood as a cache formed during the first moments of the settlement of the basin, and fractures are related to a ritual behavior. This broadens the considerations on caching in southern Patagonia and about hunter-gatherer occupations in the glacial basin of lakes Tar and San Martin.